In this question, we're trying to find how many bales of hay the donkey eats in 21 days.
We know that the donkey eats 3/9 of a hay bale a week.
Lets turn this into a whole fraction to make it easier to find the answer:
The donkey would eat 9/9, or 1 hay bale, in 3 weeks.
We know that 3 weeks is equivalent to 21 days (1 week = 7 days), so our answer would be one hay bale.
Answer:
One hay bale.
